The calculated distance (air line) between Rhosllannerchrugog and Birkenhead is approximately 27 miles respectively 43 kilometers.
By car or train, the actual journey to Birkenhead is certainly longer, as only the direct route (as the crow flies) between Rhosllannerchrugog and Birkenhead has been calculated here.
Air line (approximately)
43 kilometers
23 nautical miles